Furosemide × Hydrochlorothiazide

Furosemide acts at the loop of Henle and hydrochlorothiazide at the distal tubule. Together they remove more water and sodium and can add to potassium loss (hydrochlorothiazide SmPC).

Weakness, dizziness, thirst, less urine, rising creatinine; in older people, a risk of falls from a sudden drop in blood pressure on standing. Low potassium causes muscle weakness, cramps, palpitations and an irregular heartbeat, which is especially dangerous in patients taking digoxin.

The Spanish hydrochlorothiazide SmPC does not recommend combining it with drugs that cause potassium loss and names furosemide among them. If the combination cannot be avoided, for example in oedema that does not respond to a single diuretic, blood potassium is checked regularly (hydrochlorothiazide SmPC).